Page 18 - Climate Control News Magazine Feb 2019

Natural Refrigerants
Charge sizes may vary but
cascade systems are here
NATURAL REFRIGERANTS ARE BEING USED IN A WIDER ARRAY OF APPLICATIONS THAN EVER BEFORE, ACCORDING TO THE LATEST DATA FROM COLD HARD FACTS 3 (CHF3).
IT SHOWS THAT Australia is on track to phaseout HCFCs by 2030 in accordance with the Montreal Protocol.
It also shows that the use of natural re- frigerants in Australia is evolving with
many factors shaping this emerging market. Compiled by research firm, the Expert Group, and commissioned by the federal Department of Environment, CHF3, provides wide ranging in-
sight into local natural refrigerant trends.
One segment of the market that is leading the charge in trialling new refrigeration systems is
the retail sector, particularly supermarkets. This is being achieved with the active adop- tion of ‘cascade’ refrigeration systems that employ a smaller charge of high GWP HFC in the primary cooling loop, and a charge of CO2 in a secondary refrigerant circuit (i.e. a large store with 1,000 kg refrigerant charge com- prising 2/3 HFC-134a and 1/3 CO2). Cascade
systems are now regularly being specified for newly built large supermarkets.
The first HFC/CO2 cascade refrigeration sys- tem was installed in Australia in 2005 by Coles and other varieties were trialled including an ammonia/CO2 cascade system.
There are now more than 800 of these ad- vanced refrigeration systems in operation in Australian supermarkets, according to the CHF3 Report.
The technology formats and charge sizes in cascade systems vary significantly, however a new generation of CO2 trans-critical technology is rapidly evolving. The CHF3 Report points to a mix of technology enhancement add-ons includ- ing booster systems, parallel compression groups, ejectors, adiabatic coolers, evaporative pre-cooling, indirect evaporative/dew point coolers and mechanical sub-cooling.
“Many of these innovations seek to manage
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